Wheel assistance

Hi
New to this so be kind.
I have a specialized cross trail which is a great hybrid running 700c’s.
I want to use it a bit more like a mountain bike can I replace the rims on a straight swap for 29ers with MTB tyres?
Have tried looking for 700c tyres with a wide enough profile but don’t seem to be able to find any sufficient
Help appreciated

Although theoretically 29" and 700c are the same, there are several factors to consider, and you may run into compatibility issues depending on the specific rim/tire combo. Also make sure that the frame is wide enough, and that there will be enough clearance all around, as wider tires will increase the total diameter of your wheel more than skinny tires.

You may wish to read Sheldon Brown’s article on tire sizing.
http://sheldonbrown.com/tire-sizing.html